1) We take/accept your orders round-the-clock. (This refers to online shop.)
2) The minimum amount per order is 100 UAN./ The minimum price per order amounts to 100 UAN.
Which variant is grammatically correct?
1. Remove the hyphens from "round the clock". You can use either "take" or "accept".
2. Your first suggestion is more natural.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.